1. Field of the Invention
The present invention relates to a communication apparatus, a communication system, a communication method and program. More particularly, if a confirmation response to the reception of a transmission signal is to be issued, if it is judged that transmission data is stored, the transmission data is added to the confirmation response to generate a transmission frame to be transmitted.
2. Description of the Related Art
A communication system for bidirectional data transmission uses full duplex communications capable of data transmission in two ways at the same time, and half duplex communications capable of data transmission only in one way at a time. As the communication system of half duplex communications, for example a wireless LAN (Local Area Network), a bus type network and the like are known.
In the communication system of half duplex communications of this type, in order to prevent collision of data transmitted from a plurality of users at the same time, it is checked before transmission whether transmission is under execution or whether data is now transmitted to its own apparatus, and if it is judged that there is no data collision, data transmission is executed.
The invention disclosed in Published Japanese translation of a PCT application No. 2003-523136 describes that in data transmission, not only a data packet but also a piggyback packet are transmitted, the piggyback packet including information on a physical layer system itself, transmission line characteristics of a communication network and the like.